3com Corporation

3 Com Corporation

Intel Corporation

Wen-Tsung Tang

David A Kranzler

Jorge E Caviedes

Ruchi Wadhawan

Peter Si-Sheng Wang

W Paul Sherer

Mahesh M Subedar

William Paul Sherer

Ismail Dalgic

Rony Ferzli

Ching-Yao Chu

Edwin Ibe

A method includes detecting vertical edge pixels in an image and analyzing the detected vertical edge pixels by horizontal location in the image to detect a spatial periodicity in the detected vertical edge pixels. The method further includes detecting horizontal edge pixels in the image, and analyzing the detected horizontal edge pixels by vertical location in the image to detect a spatial periodicity in the detected horizontal edge pixels.

Method and apparatus for blocking artifact detection and measurement in block-coded video

A distributed arbitration scheme for a network. Ports in a network device determine which port in a set of ports may broadcast a packet onto a bus in the network device. A method of transmitting data between a set of ports sharing a bus in hub is described. The set of ports includes a first port, and the method comprises the first port receiving a packet, the first port requesting the bus, and, if another port is requesting the bus, the first port transmitting the packet to the bus if the first port has not transmitted a packet later than the another port requesting the bus. A system using two clocks of different speeds in a network device device. The hub has at least a port. The port has an internal data path having a first width. A bus is coupled to the port. The bus has a data path that has a second width. The second width is greater than the first width. The hub includes a first clock that has a first frequency and is coupled to circuitry in the port for clocking internal data transfers. The hub includes a second clock that has a second frequency less than the first frequency, and the second clock is coupled to circuitry in the port for clocking data transfers with the bus.

Distributed arbitration scheme for network device

A distributed arbitration scheme for a network. Ports in a network device determine which port in a set of ports may broadcast a packet onto a bus in the network device. A method of transmitting data between a set of ports sharing a bus in hub is described. The set of ports includes a first port, and the method comprises the first port receiving a packet, the first port requesting the bus, and, if another port is requesting the bus, the first port transmitting the packet to the bus if the first port has not transmitted a packet later than the another port requesting the bus. A system using two clocks of different speeds in a network device. The hub has at least a port. The port has an internal data path having a first width. A bus is coupled to the port. The bus has a data path that has a second width. The second width is greater than the first width. The hub includes a first clock that has a first frequency and is coupled to circuitry in the port for clocking internal data transfers. The hub includes a second clock that has a second frequency less than the first frequency, and the second clock is coupled to circuitry in the port for qualifying data transfers with the bus.

Dual clocks for network device

A method for rate-based flow control protocol on a ring topology network utilizing ethernet packet format and ethernet equipment. The method operates on a communication network communicatively coupling a plurality of network nodes each representing a local area network (LAN). The method for controlling a transmission of a data packets on the ring-topology communication network uses the following steps. A flow path is determined for data packets in the communication network. In another step, limits are calculated for the flow paths of the data packets with respect to each of the network nodes such that the data packets have controlled access to transmit on the communication network. In a final step, the transmission of the data packets on the flow paths is controlled according to the limits and using a packet format and equipment that is directly compatible with the local area network.

Rate-based flow control protocol on an ethernet-over-ring communications network

An improved computer network and network device uses characteristics of prior art shared network protocols to control the flow of data and access to the network among a group of transmitting nodes. The invention determines which nodes wish to send data when a collision occurs by detecting and recording which nodes participated in a collision. A scheduling routine is designed to give each connected node a chance to send. A transmission control mechanism is used to prevent a subset of transmitters from transmitting while allowing one ES to transmit without experiencing a collision. The invention has a number of applications including within an improved ethernet repeater in a multimedia ethernet.

Method and apparatus for controlling latency and jitter in shared

In a backplane architecture for a logical stackable Ethernet repeater for an Ethernet network having a plurality of stackable repeater modules, each one of the stackable repeater modules being connectable via bus-type signal lines to one another for communicating packets via bus-type signal lines, and each one of said stackable repeater modules including a plurality of ports for connection to stations, a method is provided for communicating management information wherein a management module collects information about packets on the backplane from repeater modules, and the repeater modules transmit packet information only via bus-type signal lines. In a specific embodiment, transmitting comprises appending after each packet at each source port of each repeater module an information footer having a select number of information units, and conveying each packet with the information footer on the bus-type signal lines. The management module reads the information footer from the bus-type signal lines to collect information about the source of each packet and compiles statistical information from direct interpretation of each packet.

Method for in-band communication of management information in a

A scalable CSMA/CD repeater is based on polling and collision resolution logic, and slot time and interframe gap negotiation logic controlled by the repeater itself. The repeater based polling and collision resolution provides central control of the backoff and retry algorithm of each connected MAC unit. Thus, the MAC unit does not rely on random backoff mechanisms that significantly degrade performance of prior art systems. Furthermore, the retry by a MAC unit after a collision is managed by commands received from the collision resolution logic in the repeater. The repeater based collision resolution logic ensures that all ports involved in a collision have a fair opportunity to forward a packet without being blocked before enabling all the ports in the network to freely compete again. Furthermore, the negotiation of slot time and interframe gap allows for tight control of delay parameters in the network which are involved in collision resolution and scaling of the technology with increasing MAC unit processing speeds.

Scalable CSMA/CD repeater

A Class II stackable 100 Mbps Ethernet repeater architecture achievable by use of two different types of wired-OR interconnection in an Ethernet backplane, a Bus Transceiver Logic (BTL) wired-OR to selected control, data and clock lines, and a high-speed Transistor-Transistor Logic (TTL) which is wired-OR'ed together in three-level logic on a common activity signal line. The backplane has sufficiently low signal latency to permit two logical repeaters to be connected together with at least eight stackable repeater modules in each logical repeater, each repeater module having thirteen to sixteen station ports to support as many as 254 stations in a 100 Mbps environment with a diameter of 205 meters, which is up to 8.5 times greater than previously achievable.

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Saratoga, CA, United States of America

Wen-Tsung Tang